With his cybersecurity measure stalled by policy differences and partisan wrangling, Sen. Joe Lieberman (I-Conn.) urged President Barack Obama on Monday to issue an executive order to put safeguards in place.

"I urge you to use your executive authority to the maximum extent possible to defend the nation from cyber attack," Lieberman, chairman of the Homeland Security and Governmental Affairs Committee, wrote in a letter to the president.

Lieberman's legislation failed on a procedural vote in early August after a disagreement between Democrats and Republicans over what amendments would be considered.

Lieberman wrote that he the believes the disagreements that derailed the bill in the summer are unlikely to ease after the elections, when Congress is expected to meet for a lame-duck session.

"Of course, I hope and prefer that the Senate passes cybersecurity legislation and works with the House to get a bill to your desk before the end of this session," Lieberman wrote. "Though it is hard to be optimistic about the prospects of passing legislation in the lame-duck session, I continue to work with my colleagues to find a bipartisan and bicameral compromise."

Under the bill, the federal government, working with businesses, would be required to assess vulnerabilities in the most critical digital infrastructure and to create a set of voluntary security standards.

In lieu of legislation, Lieberman asked the president to do what he could to make sure such assessments are done.

"Under current law ... the Department of Homeland Security has clear authority, if directed by you, to conduct risk assessments of critical infrastructure, identify those systems or assets that are most vulnerable to cyber attack, and issue voluntary standards for those critical systems or assets to maintain adequate cybersecurity," Lieberman wrote. "Though executive action cannot offer private sector entities liability protections for compliance with these guidelines, I urge you to consider other incentives that you can offer by executive action to companies that own critical cyber infrastructure and decide to comply with the cyber defense standards that result from your executive order."

The letter comes as other Members have also urged White House action, including Senate Commerce Chairman Jay Rockefeller (D-W.Va.).

Lieberman added that national security experts believe that the threat of a disruptive cyber-attack is "real and imminent" and that Obama should act to protect against it.

"Countless national security leaders from your Administration and the previous Administration have made clear that the threat from cyber attack is similar to the threat we faced from terrorism on September 10, 2001 - the danger is real and imminent, yet we have not acted to defend against it" Lieberman said. "We know our adversaries are already stealing valuable intellectual property and exploiting our critical infrastructure - those systems that control our water, electricity, transportation, finance, and communications systems - to prepare for attack."